One piece gasket for complex oil pan configuration

ABSTRACT

An improved gasket is designed for use on a complex interface surface between an oil pan and an engine. The gasket is formed as a one-piece molded part and is preferably injection molded from a silicone rubber. The gasket incorporates crush limiters at each bolt hole, and dual spaced sealing beads along the sides, with a circular sealing bead surrounding each bolt hole. The crush limiters control the amount of tightening of the bolts, while the sealing beads accommodate warpage of the oil pan, or undertightening of the bolt. In other features, tabs are disposed on each side of the gasket to accommodate an oil dip stick. The user of the gasket merely removes a cutaway portion associated with one of the tabs to provide a space for passage of the oil dip stick on the appropriate side. In this way, a single gasket can be incorporated into engine configurations having dip sticks on either side. In addition, an end tab is formed on one end of the gasket, and provides a saddle to be positioned outwardly of the engine to properly position the gasket.

This is a continuation of application(s) Ser. No. 08/322,484 filed onOct. 31, 1994 now U.S. Pat. No. 5,536,023.

BACKGROUND OF THE INVENTION

This invention relates to a one piece molded gasket which is configuredto seal between an oil pan and an engine, and provide versatility in thetypes of engines in which the gasket may be used.

In the prior art, oil pan gaskets have been formed of a one-piececonstruction. Such one-piece molded constructions, however, havetypically been for more recent engine designs. In the mid-1980's, theengine and oil pan interfaces were redesigned to simplify the matingsurfaces, and facilitate the use of a one-piece gasket. Prior to thattime, multi-piece gaskets were required to properly seal on the complexinterface surfaces between the oil pan and the gasket. A one-piecegasket design that could seal on the prior complex engine configurationshas not yet been provided.

In addition when supplying gaskets for after-market use on oldervehicles, it would be desirable to allow the gasket to be modified foruse on various types of engines. In at least one model, betweendifferent model years, the location of the oil dip stick has changedfrom one side of the engine to the other. In the prior art, separategaskets have been required for each of the oil dip stick locations. Itwould be desirable to provide a gasket which could incorporate the dipstick on either side. On the other hand, the alternate accommodation ofan oil dip stick on either side increases the complexity of the sealingsurfaces, and thus makes the provision of the one-piece gasket even moredifficult.

SUMMARY OF THE INVENTION

In a disclosed embodiment of this invention, a one-piece molded gasketis provided to seal upon a complex interface surface between an oil panand an engine as were typically provided in older vehicles. The gasketincludes a pair of spaced sealing beads extending along the long sidesof the gasket which accommodate any warpage or bending of the oil panrelative to the engine. In addition, the beads compensate forunder-tightening of the bolts. In combination with the sealing beads,the bolt holes incorporate crush limiters, which are essentially steelbushings preventing overtightening of the bolts. An operator is thusprovided feedback of a properly tightened bolt, by simply tightening thebolt until it contacts the crush limiter. The crush limiter preferablydoes not extend to the full height of the sealing bead, and a circularsealing bead portion preferably extends around each crush limiter. Inthis way, the circular sealing bead compensates for misapplication oftightening torque at the bolt.

In other features of this invention, each long side of the gasketincorporates a tab designed to receive an oil dipstick. Each tabpreferably includes a cut-away portion, or alternatively a patterninstructing an operator where to cut to incorporate the dip stick onthat side. Thus, an operator may merely tailor the gasket by removingthe appropriate tab portion for the side that is to receive the dipstick. At the same time, at least one sealing bead is disposed on thetab outwardly of the removed portion, to insure an adequate seal at thelocation of the oil dip stick.

In other features of this invention, the crush limiter does not extendbeyond the face of the gasket which does not include the beads, suchthat some accommodation is provided for warpage or improper tighteningof the bolts.

Also, an end tab is preferably associated with one end of the gasket toprovide a saddle properly positioning the gasket adjacent an end face ofthe engine. In this way, an operator may easily properly position thegasket relative to the oil pan and engine, as it is being mounted.

In the most preferred embodiment of this invention, the gasket is formedof a known rubber gasket material, and in a most preferred embodiment, asilicone rubber.

These and other features of the present invention can best be understoodfrom the following specification and drawings, of which the following isa brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a gasket according to the present invention.

FIG. 2 is an end view of a first end of the gasket shown in FIG. 1 alongline 2--2.

FIG. 3 is a cross-sectional view along line 3--3 as shown in FIG. 1.

FIG. 4 is an end view of an opposed end of the gasket along line 4--4 asshown in FIG. 1.

FIG. 5 is a cross-sectional view along with line 5--5 as shown in FIG.1.

FIG. 6 is a cross-sectional view along line 6--6 as shown in FIG. 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

An inventive gasket 20 is illustrated in FIG. 1. Gasket 20 incorporatestwo opposed long sides 22 and 24, a front end 26 and a rear end 28. Thegasket 20 is configured to seal an interface surface between an oil panand an engine, and is most preferably configured to fit such aninterface in vehicles manufactured prior to the mid-1980's. Bolt holes30 are spaced generally along the sides 22 and 24, and each incorporatea steel crush limiter 32. Sealing beads 34 and 36 extend along the sides22 and 24, and a space 35 is formed between the beads 34 and 36. Therelative height of the beads to the space 35 is clear from FIG. 6. Asshown, beads 34 and 36 extend slightly away from the nominal surface ofthe gasket 20. In addition, circular bead portions 38 surround each bolthole 30.

In a main feature of this invention, tabs 40 are provided on each side22 and 24 to accommodate an oil dip stick. In older vehicles, thelocation of the dip stick has sometimes been on one side, and sometimeson the other. Thus, in the prior art, different gaskets have necessarilybeen tailored for each dip stick option. The present invention allows anoperator to tailor a single gasket to accommodate either dip sticklocation. As shown in FIG. 1, tabs 40 incorporate an indicia, such as atemplate, cut away notched pattern, or simply a line indicating where adip stick cut away portion 42 should be removed. As shown, the oil dipstick requires an opening such as is shown in phantom at 44 associatedwith side 22. The operator must merely determine which side 22 or 24 isto receive the oil dip stick, and then merely remove the cut awayportion 42 on the appropriate side. Note that the cutaway portion 42does not extend outwardly as far as an outermost sealing bead 46. Thus,proper sealing is still insured even at the location of the dip stick.The unused tab might cause sealing problems in some applications, if itwere not for the use of the sealing beads 34 and 36 which remain at theunused tab 40. Thus, no seating problems should occur. Note also thatthere are a pair of bolt holes spaced adjacent to each tab 40 such thatthe area around the non-used tab will still be properly sealed.

A front end 26 and rear end 28 connect the sides 22 and 24. The gasket20 is preferably formed as a one-piece molded part, that is preferablyinjection molded from a suitable known material. In a preferredembodiment, a silicone rubber was utilized. Alternatively, impression orother molding techniques could be used.

FIG. 2 shows front end 26 which is received between the engine 48 andthe oil pan 50, both of which are shown highly schematically. There is acurved portion 52 on end 26 to accommodate the crank shaft area of theinterface between engine 48 and oil pan 50.

As shown in FIG. 3, curved portion 52 of end 26 includes three beads 54,55 and 57 at an upper surface. Beads 54, 55 and 57 perform a sealingfunction, similar to the beads 34 and 36.

FIG. 4 shows the rear end 28, which also incorporates a curved portion56 to accommodate the crank shaft area of the interface between engine48 and oil pan 50. An end tab 58 extends beyond gasket 20 at end 28. Tab58 extends for only a small width, and does not extend beyond thecircumferential extents of curved portion 56. That is, it does notextend into the flat portions 59 on each side of curved portion 56. Endtab 58 is a positioning member, and sits outwardly of the end face ofengine 48. In a sense, end tab 58 is a saddle, facilitating thepositioning of gasket 20 on the engine 48 as it is being attached. Theend tab 58 preferably extends beneath a surface 57 of gasket 20 for anextent that is greater than one half the overall thickness of the gasket20. In one specific example, the thickness of the gasket at the sidelocations 59 was 0.152 inches, while the tab extended 0.130 inchesbeyond the remainder of gasket 20. Again, the tab provides easypositioning of the gasket relative to the engine.

As shown in FIG. 5, curved portion 56 incorporates three sealing beads60, 62 and 64. The sealing beads provides the sealing function as hasbeen described previously.

FIG. 6 is a cross section along lines 6--6 as shown in FIG. 1. As shown,crush limiter 32 is associated with the bolt hole 30. Crush limiter 32is preferably formed of a metal, and most preferably of a steel. Crushlimiter 32 prevents undue tightening of a bolt in bolt hole 32. Asshown, the circular sealing bead portion 38 surrounds bolt hole 30, andextends beyond the nominal face of the gasket 20 for an amount that isgreater than the extent of the first end 66 of crush limiter 32. In thisway, should the bolt and bolt hole 30 not be fully tightened, thesealing bead 38 still insures there is adequate sealing. A similarfunction is provided by extending the opposed face 70 of gasket 20beyond the second end 68 of crush limiter 30.

Although a preferred embodiment of this invention has been disclosed, aworker of ordinary skill in the art would recognize that certainmodifications would come within the scope of this invention. For thatreason, the following claims should be studied to determine the truescope and content of this invention.

We claim:
 1. An oil pan gasket comprising:a one-piece body including twosides and two ends, each of said ends having a central curved portioncurving away from a nominal flat surface of said body, said sides beingformed with a plurality of bolt holes to receive bolts to attach an oilpan to an engine; each of said sides being formed with structure toaccommodate an oil dipstick, said structure including a first sealingbead portion positioned radially outwardly of an area which is toaccommodate an oil dipstick, such that said first sealing portion willseal on a side of said oil pan gasket which actually receives an oildipstick, and a second sealing portion positioned radially inwardly toseal on the side of said oil pan gasket which does not receive an oildipstick.
 2. An oil pan gasket as recited in claim 1, wherein sealingbeads extend generally along the entire length of said side, and saidsecond sealing portion extending generally as a linear extension of theremainder of at least one of said sealing beads which extends along saidside.